Ella Cara Deloria was born near the town of Lake Andes, South Dakota. She was the eldest of four children born to Phillip Deloria, and Mary Sully Bordeau Deloria. Ella lived on the Standing Rock reservation and attended St. Elizabeth's mission school until she was fourteen years old. She then enrolled in All Saints School in Sioux Falls, North Dakota. She began her college education at the University of Chicago in 1910, transferred to Oberlin College in Ohio in 1911, and then went to Teacher's College at Columbia University in New York City, where she graduated in 1915. At Columbia, she became aquainted with the distinguished anthropologist, Franz Boaz, who would have a great influence on her life.

From 1915 to 1919, Ella taught at All Saints Episcopal High School in Sioux Falls. She then undertook a project from the Young Women's Christian Association that proved the benefits of physical education for Native American girls. In 1923, she went to Lawrence, Kansas, to teach physical education at the Haskell Indian School, all the while harboring a deep desire to research the traditional language and culture of the Dakota Indians.

In 1927, after being asked by Franz Boaz to teach American Indian dialects to anthroplogy students at Columbia, Ella resigned from Haskell and embarked on a career as an anthropologic linguist. She worked with Boas on Dakota research, publishing scholarly works with him until his death in 1942. Using Boas's techniques, she traveled extensively, visiting Dakota and Lakota reservations to interview elders and gather information about their langauage, beliefs, and lifestyle. She also edited and translated written texts. Ella's work resulted in several books which documented Native American myths and stories, and accounts of Dakota life. Ella also wrote Waterlily , a novel that focused on Indian life from a woman's point of view, although the book was not published until long after her death.

Ella's years of research were difficult. She existed mainly on small grants and fees from writing and speaking engagements. Honoring family obligations often made it difficult for her to continue her research. However, while taking care of her father, her sister, and her nephews, she still managed to record substantial information about Dakota life and produce a definitive dictionary and grammar. By the 1940's she was a recognized authority on their language and culture.

In 1955, Ella became director of St. Elizabeth's mission school, a post that she held until 1958. She then spent a brief time working for the Sioux Indian Museum in Rapid City, South Dakota, and serving as assistant director of the W. H. Over Museum at the University of South Dakota. To this day, Ella Cara Deloria is remebered as a true reflection of her Sioux name -- Anpetu Waste Win , or "Beautiful Day Woman, " for she was the woman with the kind and gracious nature who so carefully studied and then created the fullest account of the culture, language, and traditions of the Dakota people.